#Parallel to serial converter timing code

Reports an example of serialization error. Figure 5 Parallel to Serial ModelSim VHDL simulation ZOOM-IN As clear after 5 clock cycle of вЂњo_dataвЂќ equal to zero, the signal goes to one for one clock cycle, then to zero for the last two clock cycles. In Figure 5 is highlighted the ZOOM-IN of the serial conversion of the parallel pattern вЂњ00000100вЂќ. The input byte to be serialized is re-parallelized in the byte signal. Reported an overview of the parallel to serial converter VHDL code. The serial to parallel conversion is identified by the signal byte in figure. In the testbench is used a serial to parallel converter to verify the serialization. It depends on the convention you are using. First serial output bit is the MSB of the input parallel data.

#Parallel to serial converter timing code

In Figure4 is reported a simulation of the parallel to serial converter VHDL code above. The clock is set to 10 ns, so 80 ns mean 8 clock cycles. In the simulation of all the figures below, It is clear that the FIFO depth shall be sized depending on the input data timing and, in any cases, the input data rate shall be less than or, at least, equal to the output serial data rate as in equation EQ1 ParallelDataRate <= SerialDataRate * N EQ1 Parallel to serial converter VHDL simulation results The read fifo logic will enable the read fifo data each 1/N clock cycles. If you need to handle different input timing you can implement a simple input FIFO logic in order to buffer the incoming parallel data. I mean, if the parallel data is not yet totally serialized, no other input data can be processed. The error detection logic rises the вЂњ o_error_serialize_pulseвЂќ if the input data enable is high during the serialization process. In the VHDL code is implemented an error detection logic. Signal r_data : std_logic_vector(G_N-1 downto 0) O_error_serialize_pulse : out std_logic) I_data : in std_logic_vector(G_N-1 downto 0) Figure 2 Parallel to Serial conversion exampleДЄn example of Parallel to Serial converter The serializer section takes N clock cycles to output the serial data stream. The parallel input to the module shall be at a rate of less than or equal to 1/N clock cycles. Let assume the parallel data bus of the Parallel to Serial converter to be N bit. Parallel to Serial converter VHDL code example If you need to transfer 16-bit data 1MHz the serial data stream speed shall be at least greater than 16 x 1 MHz = 16 MHz. Same data rate you need to use a higher speed in data transfer. Figure 1 FPGA connection Parallel vs SerialД¬ould be to serialize the parallel data using less connection. As you can see, these are a lot of wires! Moreover, a skew between the bits in the parallel data bus can affect the connection integrity.

For instance, if we need to transfer a data bus of 16 bits between twoДifferent FPGA at a rate of 1 MHz, we need to connect at leastДЎ6-bit data + 1 bit enable + 1 bit clock = 18 wires running 1 MHz. From two different devices, the simple way is to use the minimum numbers of